Wednesday, November 7, 2018

Yellow-browed Warbler and other rare autumn vagrants

During October and November each year, Yellow-browed Warblers (Phylloscopus inornatus) appear in the Algarve and in increasing numbers over the past five years. These tiny Siberian vagrants go often undetected, especially when they are silent. This Ind. here however was very vocal (as they often are) and I found it accidently when walking a dog in a park ("Mata de Liceu") in the middle of Faro (!) yesterday afternoon, 06-Nov-2018. It seemed to live in- and around a single, massive Cork Oak, but showed in an Araucaria tree, for the photos I include here. It may overwinter at this spot, as another one did last winter, only a couple of hundred meters away. Listen to their diagnostic two syllable calls here: xeno-canto. An overview of the development of records of this species in Portugal over the past three decades is here on Aves de Portugal.

A similar, but yet smaller and rarer autumn leave Warbler is the Pallas's Leaf Warbler (Phylloscopus proregulus) distinguished by a yellowish central crown stripe and yellowish/light greenish rump. This species has only three records for Portugal so far, including a bird that was seen from the 27th to the 31st of December 2017 and found by a visiting Swedish birder at "Fonte Benémola", a valley in the lime stone belt (Barrocal) of the Algarve, not far from Loulé, with a high diversity of plants and birds found along a stream with a dense river gallery. The finder detected the hovering bird, showing its characteristic light colored rump patch. I have been there to "twitch" the bird - not an easy task, since it was silent and using quite a big area along the valley. At the end of the day however, it always showed near a little dam in the river for some moments, allowing some quick photos and observations in the fading light of a winter day... what a fascinating little visitor. An interesting and useful autumn leaf Warbler photo ID-Guide is here on Bird Guides.

Red-backed Shrike (Lanius collurio) is also extremely rare in the Algarve, but there is a breeding population in the north of Portugal (Gerês) and I have observed them there, only a couple of hundred km away. Why is it hardly ever seen in the Algarve, despite beeing a Trans-Sahara migrant, wintering in Southern Africa? Researchers found out, that the entire European population migrates around the eastern Mediterranean and only then southwards, meaning for the populations in Western Europe (including north Portugal) to migrate eastwards, instead of southwards! The scientific paper with these findings is here: Article
So I was quite exited, when I found a juvenile of this species a couple of weeks ago near a beach (Praia de Loulé Velho) between "Vale do Garrão" and Quarteira ! I took several "phonescoped" videos with the Iphone through the brilliant Swarovski ATX-85-telescope, using also the Swarovski adapter. Here you can watch two of them: Red-backed Shrike (1) and Red-backed Shrike (2)
The second, shorter video, shows the plain reddish-brown (slightly barred) upperparts and the non-graduated tail, when paused at the right moment, thus excluding other vagrant Shrike species, among them Brown Shrike (Lanius cristatus). To distinguish it from the here common Woodchat Shrike (Lanius senator) have a look here: pdf. A very good article on the Id-problematic of Red-backed-, Isabelline- and Brown Shrikes is here on Dutch Birding.

Green Heron (Butorides virescens) at Lagoa de São Lourenço (Quinta do Lago, Loulé) on October, 24th 2018. This bird is the 1st for continental Portugal. Photo:GS.

One of the "highlights" of this rarities-season in the Algarve so far, has been the finding of a Green Heron(Butorides viriscens) at the golf-course lake of Quinta do Lago around the 20th of October. The small Heron had been seen by several people, but misidentified as a Little Bittern (!) at first and so the news about the "Mega" arrived at the local birding comunity with a delay. This North American bird must have been "carried over" by one of the severe Atlantic storms in October and its still at the location today. Meanwhile a second Ind. has been found near Lisbon. Most fascinating for me was witnissing this birds clever "fishing-skills". It at first catches an insect (wasp, dragonfly) only to then place it deliberately on the surface of the water right in front of itself and waites patiently for a fish to appear and take the bait. Then it strikes... interesting question how a behavior like this becomes genetically fixed (as it surely is on this species, just like a spider "knows" how to web...).
A Red-knobbed Coot (Fulica cristata), also called Crested Coot :) was on the same lake.

A Marsh Sandpiper (Tringa stagnatillis) is for the third consecutive winter now at a place between Faro and Olhão
(Parque Natural da Ria Formosa). Photo:GS.

While Grey-and Red-necked Phalaropes are already very scarce, but are still seen anually in the Algarve, the North American Wilson's Phalarope (Phalaropus tricolor) is truely rare. One bird in winter plumage has been found now in a rice field near the town of Lagoa some days ago and was still there today. It can be distinguished from its relatives by the longer bill and neck, as well as yellowish legs and the lack of a wing bar, among others.
These rice fields are extremely bird rich as they offer a lot of food for the birds. Crustaceans, like the invasive Louisiana Crayfish (Procambarus clarkii) for example. Hence the Phalarope shared the site with 1000+ Glossy Ibis (!), flocks of White Storks, Greater Flamingos and Eurasian Spoonbills, Lots of Black-winged Stilts, Black-tailed Godwits, Ruff, Common Snipe, Green Sandpiper, Water Pipit etc. I include here some pictures and two videos from yesterday. This is an exiting time here in the Algarve!